Saint Simeon the New Theologian

I pray, you brother and sisters: let us strive with every means at our disposal to know ourselves. Then each one of us, starting with this self knowledge, will be able to discover what is too high for us. We need know ourselves so well that we can say like David: "I am worm and not a man " (Psalms 22:7) or like Abraham: "I am dust and ashes" (Genesis 18:7). Otherwise it will be impossible to understand even the smallest part of the Word of God, to interpret it in a spiritual way worthy of the Spirit of wisdom. Without humility it is not possible to become recipient of the gifts of the Spirit.

Saint Simeon the New Theologian

Source: Daily Lives, Miracles, and Wisdom of the Saints and Fasting Calendar